The function of suppressing overpronation while running is called “stability (performance)”. Such stability performance is regarded as one of the most important functions for a running shoe. Techniques known in the art for suppressing the overpronation include a structure in which a high-hardness member is provided on the medial side of the midsole (U.S. Pat. No. 6,199,302 B1), and a reinforcement unit placed in the middle foot portion of the sole so as to suppress the torsional deformation of the sole.